Objective To explore the influence of Mycoplasma pneumoniae (MP) infection on the treatment effect and prognosis of children with idiopathic thrombocytopenic purpura (ITP). Methods A total of 78 children with ITP treated in our hospital from January 2016 to June 2019 were selected. They were divided into MP-negative group (48 cases)and MP-positive group (30 cases) according to MP infection. The selected children all received conventional ITP treatment such as Prednisone and symptomatic support for hemostasis. The clinical efficacy, clinical indicators, inflammatory factor, immune function indicators and recurrence rate of the two groups were recorded and observed. Results The total effective rate in treatment in the MP-positive group was 70.00%, lower than that in the MP-negative group of 91.67%, and the recurrence rate in the MP-positive group was 33.33%, higher than that in the MP-negative group of 8.33%, the differences were statistically significant (P<0.05). In the MP-positive group, the hospital stay and rash subsided time were (15.68±0.71) d and (10.49±1.53) d, longer than those in the MP-negative group of (11.27±0.59) d and(8.31±1.04) d, the differences were statistically significant (P<0.05). In the MP-positive group, the interleukin-6 (IL-6),interleukin-17 (IL-17) and CD8+ were (23.28±2.34) pg/ml, (70.19±12.28) pg/ml and (42.37±7.61)%, higher than those in the MP-negative group of (16.32±1.65) pg/ml, (58.67±10.51) pg/ml, and (35.97±6.50 )%, CD4+/CD8+ and natural killer (NK) cells (16++56+) were (1.03±0.42)% and (6.91±0.58)%, lower than those in the MP-negative group of (1.67±0.63)% and (11.08±1.52)%, the differences were statistically significant (P<0.05). Conclusion The inflammatory response of ITP children with MP infection is aggravated and there is immune dysfunction. The conventional treatment is not effective, and scientific and reasonable treatment for the etiology is needed to enhance the therapeutic effect of ITP and improve the prognosis.